Circuit-breaker.



PATENTED JUNE 7, 1904.

1?. L. SESSIONS. GIRGUIT BREAKER.

. APPLICATION FILED JUNE 16. 1902.

2 SHEETS-SHEET 1".

N0 M o DEL.

THE NORRIS PETERS CD PNOTO-LITNOE WASHINGTON, D C.

UNITED STATES Patented June '7, 1904.

PATENT OFFICE.

FRANK L. SESSIONS, OF COLUMBUS, OHIO, ASSIGNOR TO SIER'IENS 8; HALSKE ELECTRIC COMPANY OF AMERICA, A CORPORATION OF NElV JERSEY.

CIRCUIT-BREAKER.

SPECIFICATION forming part of Letters Patent N 0. 762,204, dated June 7, 1904.

Application filed June 16, 1902. Serial No. 111,820. (No model.)

To all whom it may concern.-

Be it known that LFRANK L. SEssIoNs,a citizen of theUnited States, residingat Columbus, in the county of Franklin and State of Ohio, have invented certain new and useful Improvements in Circuit-Breakers,of which the following is a specification.

My invention relates to improvements in electric switches of that class familiarly known as circuit-breakers and which are designed to automatically break or shunt the circuit in which the switch is connected whenever the volume of current flowing in the circuit exceeds a certain predetermined limit.

Among the objects of the invention are to provide at a minimum cost a construction which insures a very perfect and certain. closing-contact between the main contacts2 a, a contact-extending throughout the full area of the contact-surfaces of said parts-to provide a switch having auxiliary carbon or equivalent contacts which constitute the final opening-points of the switch, and which contacts are so arranged and supported as to insure a more perfect yielding contact with each other than has heretofore been attained in similar switches; to provide a construction in which by the change or substitution of a single part the capacity of the switch as determined by the amount of current which will operate to open the circuit may be varied at will within reasonable limits; to provide improvements in the details of construction of the switch rendering it economical to manufacture and at the same time durable and reliable, andin general to provide a simplified and improved device of the character referred to.

The invention consists in the matters hereinafter described and more particularly pointed out in the appended claims and will be more readily understood by reference to the accompanying drawings, in which Figure 1 is a plan view of a switch embodying my invention, the switch. being shown in closed position. Fig. 2 is a side elevation of the same, a part of the handle being broken away to reduce the size of the figure. Fig. 3 is a rear end elevation of the switch shown in Figs. 1 and 2, drawn on a larger scale. Fig. 4 is a transverse sectional view of the solenoid looking toward the front end of the switch. Fig. 5 is a side elevation of one of the interchangeable conductor-bars having a larger current-carrying capacity than that shown in position upon the switch. Fig. 6 is a perspective view of one of the laminated contact devices. Fig. '7 is a sectional view of details hereinafter described. Fig. 8 is a dctail perspective of part of the devices for yieldingl y and oscillating] y supporting the contactplates carried by the base-block.

Referring to said drawings, A designates a base-plate of insulating material upon which are mounted two contact-supporting plates B B, arranged in the present instance parallel with each other at a considerable distance apart, so as to extend longitudinally of the base-plate and permanently secured to the base by screws, as usual. Each of said contact-supporting plates is provided at one end (for convenience of description hereinafter designated the front end) with a slightlyelevated flat seat 6, as shown most clearly in Fig. 2. Upon each of said seats is mounted a contact device C, consisting of a plurality of thin leaves or laminae l) superposed upon each other and secured rigidly upon the seat by means of screws or bolts If, inserted through plates 7), arranged to overlie the front end of each contact device, passing through said leaves and threaded into the contact-supporting plate beneath. The length of each of the leaves constituting the contact device is greater than the length of the seat upon which they are mounted, and they are so arranged thereon that their rear ends project freely beyond the seat, so that the rear end of the contact device as a whole is capable of yielding downwardly under pressure. In order to afford a suitable contactsurface for a contact-bar which engages the contact devices ina manner hereinafter described, the projecting ends of the leaves are dressed off obliquely and made successively shorter from the lowermost upwardly to form a beveled contact-surface b".

D designates as a whole a double switchlever standard, comprising two standard members (Z (Z united by means of an integral yokeshaped bar (Z and secured'rigidly upon the base a short distance in front of the contactsupporting plates 1) and at equal distance on each side of a line passing centrally between the said supporting-plates. Each standard member is provided at its rear side, near the upper end thereof, with a pivot-supporting ear (Z which ears are provided with pivot-apertures arranged in alinement with each other.

E designates a switch-lever bifurcated or provided with arms 6, adapted to fit between the ears (Z and pivotally secured thereto by means of pivot-pins (Z Said lever comprises an upwardly or outwardly extending member E, provided with a suitable shank, to which is attached an insulating-handle E and with a rearwardly or downwardly extending member E provided with laterally-extending lugs or supports 0', to which is attached a transversely-extending contact-bar E of suitable length to extend across and engage both contacts Cand having its lower surface arranged at a suitable angle to insure accurate contact with the beveled ends of the leaves forming said contacts C.

In order to prevent sparking between the contacts C and the contact-bar E, the switch is provided with auxiliary or secondary carbon contacts constructed and arranged as follows: Referring to Fig. 3, F F designate carbon contacts, desirably and as shown herein having the form of flat plates or slabs of carbon, yieldably supported upon the plates B B, in electrical connection with the latter and arranged to stand in upright or outwardlyprojecting position parallel or substantially parallel with each other. As a desirable means of supporting said carbon contacts in such manner as to permit them to yield laterally and at the same time to oscillate out of their normal planes to a certain extent supporting devices are provided, as follows: E F designate lugs or standards rigidly secured to the plates B B and each provided at its upper part with a pivot-stud f, upon which is mounted an upwardly-extending arm f, which is in turn pivotally engaged at its upper end with an ear or pivot-lug f secured to the carbon plate at a point intermediate of the length or height of the latter and preferably about midway of its width. The upper or free end of the arm f is normally pressed outwardly by means of a spring f desirably and as herein shown having the form of a U-shaped loop, the upper end of which rests against and embraces the upper end of the arm f, while the lower ends are coiled one or more times around the pivot f and engaged with a part of the standard, so as to tend to force the arm f outwardly. The lower ends of the carbons are each yieldably connected with the standards F in such manner as to permit them to approach the latter bodily conveniently by means of U-shaped sprin gs f one arm of each of which is secured against the inner side of the carbon, while the opposite arm is provided outer sides of the pivot-ears d and engaged with the pivots (Z of the latter. At its rear end said lever is provided with a tran'sverselyextending bar G, mounted thereon in a manner similarly to the connections between the lever E and bar E, hereinbefore described, and carrying at each end a depending carbon contact-plate G adapted to respectively engage the contact-plates F. Conveniently the contact-plates G are attached to the bar G by means of L-shaped plates g, one part of each of which embraces the outer surface of the contact-plate, while the other part, bent at right angles to the part embracing the plate, is carried beneath the bar Gr and rigidly secured thereto by means of suitable screws or otherwise. The contact-plates aredesirably made rigid withthe supporting-plates g by means of screws or bolts 9 inserted through saidparts and engaging washer-plates g mounted upon the inner sides of the contacts.

In order to prevent the lower or free ends of i the contact-plates G from yielding outwardly when brought into contact with the plates F. spring-plates 9* are mounted upon the said contact members F and arranged to extend upwardly in position to yieldingl y engage the outer surface of the plates g, said plates being desirably and as herein shown formed by extensions of the inner supporting-platesf as indicated most clearly in Fig. 3. In order to secure a more uniform spring action, said plates g and f are divided vertically to form a plurality of independently-acting fingers.

In the operation of the switch the contactbar E* is first lifted out of contact with the contacts C, and thereafter the carbon contacts are separated, while in the closing of the switch the operation is the reverse. 7 In order to thus move the switch-lever G through the medium of the principal switch-lever E, the latter is provided with a boss 0 upon its upper side, which is arranged to engage a similar boss 5 formed upon the lower side of lever G, so that as the main lever is oscillated to open the switch the, auxiliary lever will remain stationary until the two lever-arms are brought into contact, after which the lever G will be carried forward positively with the main lever.

The switch is adapted to be thrown open automatically by means of a spring, which is conveniently and as shown in the present instance made in the form of a coiled contractile spring H, one end of which is attached to the center of the bar d, which unites the switch-lever standards, while its opposite end is attached to a part of the lever E located above the pivotal axis of the latter, so that the tension of the spring tends to lift or throw over the lever. Conveniently such attachment is formed by passing the looped end of the spring through an aperture 17, formed through an integral web 0 extending between the arms of the lever. The limit of throw of the lever is determined by means of suitable stops or shoulders (F, which, as shown herein, consist of rubber blocks seated in suitable sockets (Z formed in the upper parts of the standard members and located in the path of movement of the arms 9 of the auxiliary switch-lever Gr. In order to hold the switch-levers in open position frictionally, spring-blades are secured to the standards in position to embrace and bear yieldingly against the sides of said arms 9 when the latter are in their forward position.

The switch is normally held in closed position and against movement under the influence of the spring H by means of a latch or detent mechanism adapted to be operated by a solenoid. A preferred construction of this mechanism comprises a solenoid-coil I, arranged between the standard members with its axis extending longitudinally of the switch, its front end terminal being connected with a stationary terminal J, projecting above the base-plate and the body of Which extends downwardly through said base and forms a binding-post at the lower side of the latter for engagement With one of the circuit-conductors, While the opposite terminal end of said coil is connected with one of the contact-supporting plates, as B. Desirably the solenoidcoil is constructed of a plurality of strips or thin ribbons of conducting material superposed upon each other and arranged in the form of a helix, eachstrip extending unbroken throughout the full length of the coil,.as indicated clearly in the figures of the drawings, and particularly in sectional Fig. 4c. Vithin said solenoid-coil is arranged a tubular lining or barrel Z within which in turn is arranged to it and slide a solenoid-core 1 The core 1 is provided with an axial bore, through which is passed loosely a rod K, upon which the solenoid is adapted to reciprocate, said rod being of sufficient length to extend throughout the full length of the solenoid and outwardly beyond the end of the latter a distance sufficient to accommodate the core and to project a short distance beyond the latter when it is in its outermost position. The front or outer end of the rod K is provided with a knob Z1,

which serves to limit the outward movement of the core, and is provided near its opposite end with a tappet-collark, ad ustably secured rigidly thereon, said tappet being so located that the core as it approaches the limit of its inward movement will strike against the collar and thereafter move the rod positively with it. Vith the rear or inner end of the rod K is pivotally connected a link Z5, which extends rearwardly to and is connected at its opposite end with the lower end of a swinging latch the upper end of which is pivotally supported from a standard K, mounted upon the base-plate A. The latch F is provided with a notch or shoulder k at a point intermediate of its length adapted for engagement with the toe-shaped rear end of the lever E, the arrangement being such that when the rod K is forced rearwardly by the solenoid-core the latch is oscillated through the medium of the connecting-link to release the switch-lever and permit it to be thrown upwardly under the influence of the coiled spring H.

J designates a terminal substantially similar to the terminal J, the body of which extends upwardly through the base A and is electrically connected with the contact-supporting plate B, this terminal constituting the means for connecting the lead or conductor of the circuit leading to the opposite pole from that connected with the terminal J. When the switch is closed, the path of the current is from the terminal J through the solenoid to the contact-supporting plate B and contact C, carried thereby, thence through contact-bar E to the opposite contact C and contact-supporting plate B and thence out through terminal J. \Vithout other connections it will be obvious that the entire current would be carried through the solenoid; but in order that the switch may be used for currents of various strength and at the same time so adjusted that it will be thrown open only when the strength of current exceeds the normal current for which the switch is adjusted I provide means for shunting a determined proportion of the current around the solenoid. To this end I provide a series of conductor-bars L, each adapted to be connected with and extend from the terminal J beneath the base-plate to a similarlyconstructed binding-post J located beneath the contact-supporting plate B and arranged to extend up through the base and forming electrical connection with said plate. Said conductor-bars as a whole are desirably comprised of one or more straps or bars Z, united at their ends with nut-shaped sockets or collars Z, adapted to lit upon the terminals J and J", the several units of each conductor-bar (when the latter is composed of more than one) being each made of the same definite carrying capacity, so that the operator may know at a glance what proportion of the current will be carried through the shunt-circuit of the switch. Obviously by simply substituting conductorbars having different numbers of units the switch may be adjusted to open at any desired strength of current.

The operation of the switch has been sufficiently indicated in connection with the description and need not, therefore, be again detailed. It maybe noted, however, that in use the switch will ordinarily be secured with the base in avertical position, that end of the switch which for convenience of description has been herein designated as the rear end being placed uppermost, so that the core of the solenoid will normally rest against the knob at the lower end of the rod K and will be drawn up against the force of gravity by magnetism when the solenoid is energized to the required degree.

It will be noted that by reason of the peculiar construction and arrangement of the main or laminated contact devices not only will the yielding leaves or laminae adapt themselves to any inaccuracies of adjustment or construction of the contact-bar, but each of said leaves will come into contact with said bar with a slightly rubbing or sliding movement, so that the contact-su rfaces will be kept bright and in most efficient condition.

The feature of supporting one of each pair of the carbon contacts so that it may yield bodily and at the same time oscillate upon its bearings is obviously an important one, inasmuch as it insures that the meeting faces of the contact devices shall rest squarely against each other throughout the entire opening and closing movement of the contact regardless of whether or not the movable member is so mounted as to move accurately into engagement with the fixed member. It will be furthermore obvious that the advantageous results due to thus mounting a pair of contacts are not confined to carbon contacts or contacts of equivalent material; but, on the contrary, this mode of mounting is applicable to contacts of any conducting material, with similar advantageous results.

VVhileI have herein shown and described a preferred embodiment of my invention, yet it will be obvious that the invention may be otherwise embodied without departing from the principles of the same, and I do not, therefore, wish to be limited to the details shown herein except as made the subject of specific claims.

I claim as my invention- 1.- In an electric switch, the combination of a fixed contact device and a relatively movable contact device, each provided with a flat meeting face of extended area and adapted to contact with each other, one of said contacts being pivotally supported upon a spring-pressed arm, said pivotal engagement being arranged at a point intermediate of the contact length of the contact device and the axis of the pivot being arranged to extend parallel with, and transversely to the contact-surface of the device, whereby the contact device is permitted to yield bodily under pressure of the opposing contact device and to oscillate into posicontact, and a second yielding support connected with a part of the contact remote from the pivot-support and whereby it is held yieldably in a determined position.

2. In an electric switch, the combination of a fixed carbon contact-block and a relatively movable carbon contact-block, each provided with a fiat contact-face of extended area, one of said contacts being pivotally supported upon a spring-pressed arm and having its pivotal connection arranged at a point intermediate the length of its contact-face and with its pivotal axis extending parallel with, and transversely to, said contact-face, whereby the contact-block is permitted to yield bodily under pressure of the opposingblock and to oscillate into position to rest squarely against said opposing block, and a second support connected with a part of the contact remote from the pivotal axis, consisting of a U-shaped spring, whereby said contact-block is held yieldably in a determined position so as to insure a rubbing engagement throughout the opening and closing movement of the contacts.

3. In an automatic circuit-breaker, the combination of a base carrying a stationary con tact, a spring-actuated lever device carrying a movable contact, a pivotally-supported latch engaging the lever device and holding its contact in contact with the stationary contact, circuit devices, and a solenoid device adapted to unlatch the lever device upon the passage of an abnormal current, said solenoid device consisting of a coil having a slidable tubular core, a rod extending through said core and beyond its ends, said rod being provided with a tappet-collar at each end beyond the core, and a link pivotally connecting one end of said rod to the free end of the aforesaid latch, for the purposes set forth.

4:. In a circuit-breaking device, the combination of a pair of fiat-faced carbon contactplates adapted to overlap and slide otf and onto each other, one of these plates being movable with respect to the other, means for supporting the stationary contact-plate so that it may be oscillated and will be spring-pressed toward the other contact-plate, said means consisting of a yielding support at one end of the plate and a pivotal support connected to it at a d istance from said yielding support.

5. In combination with a base, a stationary carbon contact-plate, means yieldingly connect-ing one end of said contact to said base, so that it may be oscillated with respect to the base, one or more spring-clasps 9* connected to said contact-plate at its point of connection to the base, a lever device carrying a companion carbon contactplate adapted to overlap said stationary carbon contact-plate and fit between the spring-clasps and the contact-face of the stationary contact-plate, for the purposes set forth.

6. In an electrical circuit-breaker, the combination of a support and a member movable with respect thereto, a contact-plate carried by the support and another contact-plate carried by the movable member, said contactplates being adapted to overlap and slide onto and off each other to make and break the circuit, means for yieldingly and oscillatingly supporting one of the contact-plates, for the purpose set forth, and one or more springclasps carried by one of the contact-plates and extending over and clasping the other contactplate, whereby the two contact-plates will be held in close contact while overlapped.

7. In an electrical circuit-breaker, the combination, of a support and a member movable with respect thereto, a contact-plate carried by the support and another contact-plate carried by the movable member, said contactplates being adapted to overlap and slide onto and off each other to make and break the circuit, means for yieldingly and oscillatingly supporting one of the contact-plates, for the purpose set forth, and one or more springclasps carried by this latter contact-plate and extending over and clasping the other contactplate, whereby the two contact-plates will be held in close contact while overlapped.

8. In a circuit-breaker, the combination of a base carrying a contact and circuit devices, a spring-actuated switch-lever carrying a contact, a latch engaging the lever device and holding the contacts in engagement, a solenoid in the circuit, said solenoid consisting of a coil having a'slidable tubular core, a rod eX- tending through said core and connected to said latch, said rod being provided with tappets, for the purpose set forth.

In testimony that I claim the foregoing as my invention I aflix my signature, in presence of two sul;)scribing witnesses, this Z Lth day of May, A. D. 1902.

FRANK L. SESSIONS.

itnesses:

1*. G. ZWERNER, F. E. KooHENDERFnn. 

